Composting toilets not working as advertised

A number of B.C. public agencies say their composting toilets are not working as advertised.

Metro Vancouver and B.C. Parks are retrofitting units built with the once-celebrated green technology.

And UBC is re-evaluating five high-profile composting toilets in the CK Choi building after testing revealed problems with the by-products.

As a result, the university says it has hired a contractor to remove the solid waste to a sanitary landfill and is sending the liquid product into the sewer.

"This was really cutting edge stuff and leading the way and as it turned out, there's a piece of it that didn't work as it was originally intended," says David Woodson, UBC's manager of building operations.

"Ultimately, we do have to pump it out. The original intent was that you wouldn't have to do that. It does break down, so it's still better than just dumping it to the sewer."

Composting toilets are essentially supposed to turn human waste into fertilizer. The waste drops into a vault beneath the toilet where urine drains away from the solid component. Users then add bulking agents like wood chips to activate the composting process.

No signs of composting activity

But according to Patrick Graham, manager of parks capital projects for Metro Vancouver, three composting toilets piloted at Surrey's Tynehead Regional Park are not functioning correctly.

"Generally, the experience is that you don't see a lot of composting activity," says Graham. "We had hoped that we would see evidence of composting activity in the solid pile, which we didn't."

Graham says the composting toilets are getting rid of liquids, which make up the majority of human waste, but like UBC, Metro Vancouver is having to pump out the solid waste. He says workers have stopped adding the bulking agent, because nothing is happening.

B.C. Parks has also put out a request for expressions of interest to retrofit a composting toilet at Liard River Hot Springs Regional Park. The document says the existing toilet "fails to achieve its main objective, there are no signs of composting activity and significant odors are occurring."

Don Mills speaks for Clivus-Multrum, the company which made the B.C. Parks composting toilet.

He says the unit should work given proper maintenance and attention to the introduction of bulking agent and removal of the solid compost.

"My assumption is that what they would like is something that isn't so much green as it is magic. That is disappearance," he says.

"Obviously they're not operating the park with the aim of collecting the visitors' excreta so that it can be recycled. Their job is recreation — not recycling. So the ideal circumstance is that they don't have to have anybody spending any time taking care of a toilet system. That's a hard ideal to reach."

'Do these work?'

Metro Vancouver has contracted Geoff Hill to retrofit one of its composting toilets.

Hill founded Toilet Tech Solutions after completing his PhD at UBC in waste management and studying composting toilets at public parks in B.C., Alberta and the U.S.

He says he found samples of feces in solid piles that remained intact for years, and he claims the byproducts of the composting process often don't meet regulatory standards that would allow them to be used as fertilizer.

As a result, he says, parks are going to extraordinary lengths to remove waste from composting toilets.

"People are shoveling it into barrels and carrying the barrels out, in Yosemite they use llamas, in helicopters," he says. "And the funny thing is that now they're moving so much more volume material at the end because it's all been bulked up with wood shavings."

Hill believes one of the problems is that liquid and solid waste are not separated at source. As a result of mixing the two before the urine is screened out, he says ammonia in the feces rises to levels that cannot support the micro-organisms needed for the composting process.

Metro Vancouver is testing a device Hill developed that would use a lever attached to an outhouse door to sweep away solid waste while directing urine into a gutter.

Hill believes a better term for the technology in this region would be "dry toilets," which is used in Europe.

"Everybody pees and everybody poos. Every animal on the planet has some sort of waste stream," he says. " Because it's been labelled and shoved away in that corner as don't talk about it, or it's not something you get a doctorate in, it's obviously been neglected.

"The field has been neglected and nobody's asked the question: Do these work?"